[Brain perfusion SPECT in the prognostic assessment of stroke]

PURPOSE

To compare the diagnostic yield of CT scan and perfusion SPECT on admission and its prognostic value in clinical outcome.

METHODS

25 ischemic stroke cases were studied on admission (<24 h) and at 30-60 days by CT scan, 99mTc-HMPAO-SPECT and neurological scales. Infarct size and severity on SPECT were assessed: visually "Total Weighted Score," added value in 22 areas, and by several semiquantitative count-based indices.

RESULTS

Sensitivity: the first CT scan was positive in 24% patients, initial SPECT in 75% (73% of pure subcortical infarcts and 91% of those with cortical involvement). Localization: kappa: 0.725 between SPECT findings on admission and those in control-CT at 5 days. Extent and severity: correlations between count-based and visual indices (r: >0.719), the latter correlated slightly better with clinical scales. Both predicted similarly (Rho>0.739) infarct size in CT diagnostic scan. Early Outcome: There were statistical differences between deceased and survivors in SPECT (<24h) indices and CT-infarct size (mean 5 days), but not in neurological scores on admission. Long term Outcome: Correlation of initial SPECT indices with follow-up functional scores (SNSLP, Barthel index; mean 37 days) was only significant for visual SPECT indices (Rho:0.560 to 0.620). Nevertheless the best predictor of functional status on discharge was the Barthel Index on admission.

CONCLUSIONS

1) Early SPECT has good sensitivity and accurate infarct size prediction so it can be a useful tool for deciding thrombolytic therapy; 2) Visual scores perform as well as more complex indices; 3) Infarct volume seems to be a critical determinant in vital outcome; other factors (strategic localization, etc.) might influence long term functional status.

Osteonecrosis diagnosed on MR images of the knee. Relationship to reduced bone mineral density determined by high resolution peripheral quantitative CT

PURPOSE

To evaluate if osteonecrosis diagnosed on MR images of the knee relates to reduced bone mineral density (BMD) and may be caused by an insufficiency fracture.

MATERIAL AND METHODS

Thirty-two consecutive patients (8 men, 24 women; age range 27-82 years, mean 62 years) with MR findings of osteonecrosis of the femoral or tibial condyle were prospectively included. Trabecular and cortical BMD were measured with high resolution peripheral quantitative CT in the non-dominant distal radius and the tibia of the involved extremity. One tibia was not measured due to posttraumatic deformity.

RESULTS

The mean trabecular BMD of the radius was 81% of the young-adult average peak BMD (range 19-160%). The mean cortical BMD in the radius was 86% (range 63-108%). The mean trabecular BMD in the tibia was 92% (range 28-160%). The mean cortical BMD in the tibia was 86% (range 49-132%). The values of the trabecular bone of the distal radius (tibia) were normal in 11 (15) patients, osteopenic in 12 (4), and osteoporotic in 9 (12), respectively. The cortical bone values of the distal radius (tibia) were normal in 12 (13) patients, osteopenic in 12 (12), and osteoporotic in 8 (6), respectively.

CONCLUSION

Osteoporosis and osteopenia are commonly found in patients with osteonecrosis of the knee as diagnosed on MR images. This indicates that for some patients an insufficiency mechanism may be responsible for the MR findings. However, in the patients with normal bone density other reasons for osteonecrosis may be present.

[Significance of axial rotation alignment of components of knee prostheses]

Increased internal malrotation of the tibial and femoral components affects kinematics of the patellofemoral joint and the flexion gap. A combined tibial and femoral malrotation may lead to maltracking of the patella. Isolated internal malrotation of the femoral component results in an asymmetric flexion gap. Clinically, the patients suffer from either lateral instability or medial stiffness in flexion. Lateral flexion instability leads to medial tibial pain,difficulties standing up from a chair,or instability during descending stairs or walking downhill. Medial stiffness in flexion may lead to secondary arthrofibrosis. There are three methods for determining femoral rotation by bony landmarks: (1) posterior condyles with 3 degrees of external rotation, (2) anterior-posterior axis according to Whiteside, and (3) transepicondylar axis. The transepicondylar axis approximates the flexion axis of the knee. All three bony landmarks have the disadvantage that they will not create a symmetric flexion gap in all cases. The balanced flexion gap technique seeks to achieve a perfectly balanced extension gap first, and then aligns the femoral component parallel to the tibial resection plane when the knee is under symmetric distraction in 90 degrees of flexion. The soft tissue releases for varus or valgus contraction have to be performed in extension first until the mechanical axis passes through the center of the knee, the center of the femoral head, and the center of the ankle. Using these methods, both,extension and flexion gap will become rectangular. The balanced flexion gap method has the disadvantage that the femoral component will not be aligned parallel to the epicondylar axis in some cases. It is not known which of the two methods will produce better clinical results. Rotational positioning of the tibial component referenced on the tibial tuberosity represents the most reliable method. Placing the tibial component according to the femoral component using the floating technique may increase an internal malrotation problem of the femur if present.

[Rotational malalignment of the components may cause chronic pain or early failure in total knee arthroplasty]

Rotational alignment of the tibial and femoral component plays an important role in modern total knee replacement surgery. After correct frontal alignment and proper soft tissue balancing, the rotational placement of the components represents the "third dimension" in knee endoprosthetic surgery. Improved surgical techniques with modified instruments and better rotational component positioning will lead to better functional outcomes. Patients with painful total knee arthroplasties (TKA) or early failure without evident classic implantation failures or signs of infection should be evaluated for malrotation of the components. In a prospective study in 26 patients with painful TKA and malrotation of the tibia and/or femur component, revision surgery with exchange of the components was performed. Twenty-five cases showed clinically relevant internal malrotation of the tibial component (ø 8.4 degrees ) and/or femoral component (ø 5.6 degrees ). Only one patient had 10 degrees of external malrotation of the femoral component. Combined malrotations of the tibia and femur were found in ten knees (38%). After revision surgery and correction of malrotations, 20 patients (78%) were scored with excellent and good results. Patients with painful TKA resistant to conservative therapy and evident malrotations of the component should be considered for revision surgery with change of the malrotated components.

Impact of preimplantation genetic diagnosis on IVF outcome in implantation failure patients

Implantation failure (IF) is defined as three or more failed IVF attempts, and preimplantation genetic diagnosis (PGD) is being used in these patients to improve IVF outcome. PGD was performed in 49 implantation failure patients with a mean number of 4.2 +/- 1.6 previous IVF failures, and in nine fertile controls. Fluorescence in-situ hybridization (FISH) on blastomeres from biopsied day 3 embryos was performed for chromosomes 13, 16, 18, 21, 22, X and Y. There was a significantly higher rate of chromosomal abnormalities (67.4%) compared with controls (36.3%). In 57 cycles, a pregnancy rate of 34.0% and an implantation rate of 19.8% was observed in implantation failure patients compared with controls (33.3 and 24.1% respectively), with all the pregnancies in the implantation failure group coming from the transfer of at least one chromosomally normal blastocyst on day 5. It is concluded that in IVF patients, use of PGD along with blastocyst transfer improves IVF outcome.

Prior aspirin use in unstable angina patients with modified plasma inflammatory markers and endothelial nitric oxide synthase in neutrophils

BACKGROUND

Prior use of aspirin in patients with acute coronary syndrome has been associated with a lower incidence of acute myocardial infarction. The aim of this study was to explore if prior aspirin therapy in unstable angina (UA) patients could modify systemic inflammatory markers such as interleukin-6 (IL-6), tumour necrosis factor-alpha (TNF-alpha) and intercellular adhesion molecule-1 (ICAM-1) and the expression of endothelial nitric oxide synthase (eNOS) in neutrophils.

MATERIALS AND METHODS

Unstable angina was defined as transient S-T segment changes without significant increases in CK and CK-MB. We studied 50 consecutive patients admitted to hospital within 24 h after the onset of chest pain. The number of patients with prior aspirin was significantly higher (n = 32) than those not taking aspirin (n = 18) on admission.

RESULTS

Plasma levels of IL-6 and ICAM-1 were significantly increased in the UA patients when compared with the healthy control volunteers (n = 20) used as a reference for normal values. Plasma levels of both IL-6 and ICAM-1 were reduced in patients taking aspirin. There were no differences in the plasma levels of TNF-alpha between the UA patients and the control volunteers. The eNOS protein expression was also higher in neutrophils from the UA patients taking aspirin than in those not taking aspirin.

CONCLUSION

Patients taking aspirin before UA showed a lower systemic inflammatory response and higher eNOS protein expression in their neutrophils

Treatment of conjunctival lymphomas by beta-ray brachytherapy using a strontium-90-yttrium-90 applicator

We reviewed the outcome of the 10 patients (13 eyes) with localized, biopsy-proven, low-grade lymphoma of the conjunctiva treated at our Department between 1988 and 1997. All patients were treated by beta-ray brachytherapy using a bidirectional 90Sr-90Y ophthalmic applicator (Applicator SIA 2, Amersham plc). Total doses, prescribed at the surface of the applicator, varied between 40 Gy and 80 Gy. With a median follow-up of 78 months (range: 14 to 146 months), seven patients remained with no evidence of relapse (67.5% 10 year disease free survival). Local control was achieved in 10 out of 13 eyes (76.9%). Two of the three local relapses were marginal. One of these three patients also developed a metachronous lymphoma in the contralateral conjunctiva. These three patients underwent a second course of brachytherapy with 90Sr/90Y and remained free of second relapse 109, 68 and 33 months after salvage therapy. No cases of systemic relapse were observed. Late (LENT-SOMA) complications were of grade 2 in five eyes, of grade 3 in one eye and of grade 4 in one eye. Late complications of grade 2 or higher were observed in one out of five patients (20%) treated with doses lower or equal to 50 Gy and in six out of eight patients (75%) treated with doses higher than 50 Gy (P=0.086). Our data indicates that beta-ray brachytherapy was ultimately able to control most conjunctival lymphomas but carried a risk of late complications and marginal relapses that was possibly higher than the rates reported for other radiotherapy techniques.

Bacterial 16S rRNA gene analysis revealed that bacteria related to Arcobacter spp. constitute an abundant and common component of the oyster microbiota (Tiostrea chilensis)

To explore the bacterial microbiota in Chilean oyster (Tiostrea chilensis), a molecular approach that permits detection of different bacteria, independently of their capacity to grow in culture media, was used. Bacterial diversity was assessed by analysis of both the 16S rDNA and the 16S-23S intergenic region, obtained by PCR amplifications of DNA extracted from depurated oysters. RFLP of the PCR amplified 16S rDNA showed a prevailing pattern in most of the individuals analyzed, indicating that a few bacterial species were relatively abundant and common in oysters. Cloning and sequencing of the 16S rDNA with the prevailing RFLP pattern indicated that this rRNA was most closely related to Arcobacter spp. However, analysis by the size of the amplified 16S-23S rRNA intergenic regions revealed not Arcobacter spp. but Staphylococcus spp. related bacteria as a major and common component in oyster. These different results may be caused by the absence of target for one of the primers employed for amplification of the intergenic region. Neither of the two bacteria species found in large abundance was recovered after culturing under aerobic, anaerobic, or microaerophilic conditions. This result, however, is expected because the number of bacteria recovered after cultivation was less than 0.01% of the total. All together, these observations suggest that Arcobacter-related strains are probably abundant and common in the Chilean oyster bacterial microbiota.

[Sporadic Creutzfeldt-Jakob disease: phenotypic variability]

Prion disease are characterized by cerebral deposition of an abnormal protease-resistant isoform of a membrane-bound glycoprotein called prion protein. Sporadic Creutzfeldt-Jakob disease (CJDs) is the most frequent, accounting for approximately 85% of all human prion disease. The identification of a new variant of Creutzfeldt-Jakob disease has reinforced the need for a detailed analysis of phenotypic variability of CJDs. CJDs is typically characterized by rapidly progressive dementia, myoclonus, periodic sharp-wave electroencephalographic activity, and wide-spread spongiform degeneration. However, variations in clinical presentation, disease duration, as well as type and distribution of lesion have been consistently observed. The physicochemical properties of PrPsc in conjunction with the PRNP codon 129 genotype largely determine this phenotypic variability. Continued attention to clinically atypical cases is required to monitor the real incidence of CJDs. To reach this goal neuropathological examination, including the search for PrPsc, and molecular genetic analysis of human prion protein gene (PRNP) should be increasingly applied to atypical neurodegenerative diseases.

Fatty acid amide hydrolase localization in the human central nervous system: an immunohistochemical study

Recent discoveries have opened new fields for research on the biochemistry and pharmacology of cannabinoids. Among them, and most importantly, are the characterization and molecular cloning of central and peripheral cannabinoid receptors as well as the isolation of the first putative endogenous ligands that bind to them, anandamide and 2-arachidonylglycerol. The enzyme that degrades these so-called "endocannabinoids" is an integral membrane protein, fatty acid amide hydrolase. Its distribution and biochemistry in rat brain suggest that it plays a critical role in the regulation of the endocannabinoid system. However, few data exist regarding its distribution and mechanism of action in human tissues. To that end, we have studied its cellular distribution in the human central nervous system by immunohistochemistry. Using an affinity-purified antibody, we report that fatty acid amide hydrolase is localized to specific and well-delimited cell populations, including cortical pyramidal neurons, subcortical white matter astrocytes, striatal and striatoefferent projecting neurons, hypothalamic and midbrain nuclei, granular and molecular layers of the cerebellum, Purkinje neurons, dentate cerebellar nucleus, inferior olivary nuclei and others. This distribution resembles that of the central cannabinoid receptors as well as that of the enzyme distribution in the rat brain. In summary, the cellular localization of the degradative enzyme of the endogenous cannabinoid ligands in human central nervous system reveals its presence on both neuronal and glial elements and shows a significant overlapping with that of central cannabinoid receptors, mainly in areas related with motor control, confirming the notion that the endocannabinoid system plays a critical role in the control of movement.

Characterization of paint samples used in drinking water reservoirs: identification of endocrine disruptor compounds

Several migration tests are performed from various epoxy paint samples that, according to the regulation, can be used in food reservoirs such as drinking water reservoirs. The level of the organic compounds capable of producing migrations to water with special attention to endocrine disruptor compounds (EDCs) are identified and estimated by closed loop-stripping analysis (CLSA) and liquid-liquid extraction (LLE) methods coupled with gas chromatography (GC)-mass spectrometry (MS). Bisphenol A, a strong endocrine disruptor, is found in all migration experiments. Its concentration level reaches between 0.02 and 0.03 mg/cm2. The higher concentration corresponds with benzylic alcohol, which is used as a solvent and curing agent in epoxy paint. Other EDCs identified in the migration tests are phthalates, 4-nonylphenol, and t-butylphenol. The main non-EDCs identified are solvents, antioxidants, and rubber-like compounds. No great differences are found in the use of metallic plates or concrete slabs for migration experiments; only additional compounds related with the pretreatment of the concrete wall have been identified, too. In the study of a drinking water sample the same organic compounds identified in the migration test is not seen. This is probably because of the dynamic situation in a drinking water reservoir. Finally, a GC profile of a direct epoxy paint analysis is shown. The main peak identified is bisphenol A diglycidyl ether, monomer, and an active principle of the polymerization of epoxy resins based on bisphenol A. In addition, we report the recoveries of a selected group of EDCs using CLSA and LLE methods coupled with GC-MS.

[Disinfection treatment for lettuces (Lactuca sativa) and strawberries (Fragatia Chiloensis)]

The disinfection of vegetables and fruits is a treatment applied in order to reduce their natural contamination or processes to the product along the different steps of the food chain until its consumption. In the present work the effect of two disinfectants products was studied: grapefruit seed extract (400 ppm) for 10 min and peracetic acid (2000 ppm) for 1 min (action times assayed according to the manufacturer recommendations) and other additional times. The germicidal action was carried out against the natural contaminants of lettuces and strawberries, through the determination of the germicidal efficiency (%). Treated and untreated strawberries were also evaluated for flavor changes through a sensorial difference test, triangular test. None of the assayed products reached the 99.999% destruction of the natural contaminants according to the Chambers test. Peracetic acid was the most effective disinfectant, reaching the highest destruction percentages at a time lower than that for grapefruit seed extract. Sensory analysis showed no significant differences (p = .05) between strawberries with and without disinfection treatments, at the conditions suggested by the manufacturer.

Renal vascular injuries

Even today, most renal vascular injuries result in loss of renal function. Kidney salvage is not possible because of late diagnosis and the presence of severe associated injuries. Physical exam and basic laboratory tests are not sensitive; thus, a high index of suspicion is required. Repair should be attempted for all solitary kidneys and for patients sustaining bilateral injuries. All viable kidneys should be revascularized in order to increase the chances of obtaining adequate functional renal tissue. In the event that revascularization is not feasible, nephrectomy can be performed at a later time, if hypertension develops. In some cases, delayed return of function is possible, but in most cases the kidney will atrophy without producing hypertension. Most importantly, maintaining a high index of suspicion, prompt diagnostic evaluation, and judicious treatment can optimize outcome lowering the significant morbidity and mortality of renal vascular injuries.

[Carcinoid syndrome: report of a case with heart involvement and primary ovarian tumor]

A patient with a primary ovarian carcinoid tumor with extensive carcinoid heart disease, without hepatic metastases is presents. Literature was revisited, emphasizing that carcinoid heart disease secondary to an ovarian tumor is quite rare. Surgical indications relative to this patient are discussed.

Heterogeneity of Helicobacter pylori cag genotypes in experimentally infected mice

Our aim was to assess whether the Helicobacter pylori population recovered from experimentally infected mice show heterogeneity in cag genotypes. Wild-type FVB/N mice were challenged with strain Hp1 and sacrificed 8 weeks later. Direct PCR on gastric tissue was performed using primers for glmM and cagA, and for these two genes and for cagE and virB11 using DNA from the infecting and the emerging strains. The gastric tissues of two of five mice were PCR+ for glmM but not cagA. For the infecting strain, the PCRs for all four genes studied were strongly positive, but the sweeps from the emerging strains from both mice gave weaker signals for cagA and cagE. Examination of single colonies showed reduced or absent signals for cagA and cagE in relation to glmM and virB11. Serial dilution PCR of sweep isolates from the mice showed a 10- to 100-fold decrease in cagA signal compared to the infecting strain. The decrease of cagA and cagE, but not virB11, amplification and lack of cagA hybridization in Southern blots indicates a selective loss of the right half of the cag island during murine infection. This phenomenon is consistent with host-induced adaptive changes of cag genotype in the population of colonizing H. pylori cells.

Model-independent source imaging using two-pion correlations in (2 to 8)a GeV Au+Au collisions

We report a particle source imaging analysis based on two-pion correlations in high multiplicity Au+Au collisions at beam energies between 2A and 8A GeV. We apply the imaging technique introduced by Brown and Danielewicz, which allows a model-independent extraction of source functions with useful accuracy out to relative pion separations of about 20 fm. The extracted source functions have Gaussian shapes. Values of source functions at zero separation are almost constant across the energy range under study. Imaging results are found to be consistent with conventional source parameters obtained from a multidimensional Hanburg-Brown-Twiss analysis.

Effects of fish farm loadings on seagrass (Posidonia oceanica) distribution, growth and photosynthesis

The spatial extent and timing of the impact of fish farms on the distribution and performance of a Posidonia oceanica meadow were examined in an embayment of the south-eastern coast of Spain (Hornillo Bay, Murcia). Changes in seagrass distribution were determined using available seagrass mapping (from 1988, i.e., before the onset of aquaculture activities and 1998) and by successive sampling in 1994 and 1998. Environmental variables (light attenuation coefficient, water-column dissolved nutrients and organic content of sediments) together with plant performance (shoot biomass, leaf growth rate, photosynthetic activity, carbohydrate reserves, the number of leaves per shoot, epiphyte loads and herbivore pressure) were measured in plants affected by organic discharges, and were compared with those found in reference healthy plants over an annual growth cycle. Since the onset of fish farm activity, 11.29 ha of P. oceanica meadow has been completely lost and 9.86 ha significantly degraded, thus resulting in a total affected area which accounts for about 53% of the former meadow, or 7-fold the fish farming area. Unequal propagation of seagrass die-off or degradation reflects the relevance of local factors such as depth and hydrodynamism on the true extent of fish farm impact. Water transparency decreases and dissolved nutrient and organic content of sediments increases in the vicinity of cages compared to distant reference stations, thus supporting the notion of environmental gradients caused by the organic release from cages, which spreads outwards. Shoot size, leaf growth rate and the number of leaves per shoot in plants close to the fish farm decreased. Moreover, low leaf growth and low rhizome carbohydrate concentration (always relative to that found in an undisturbed area) indicated carbon budget imbalances. Since light reduction in the affected area was only modest (31% of light reaching the sea surface, while at the same depth this figure was 39% at the reference site), and light availability was well above the minimum requirement estimated for this species, neither this factor nor epiphyte overgrowth (epiphyte load was lower in the affected area) seem to explain such carbon imbalances or the observed meadow regression. Alternatively, the high herbivore pressure found in the affected zone suggests that overgrazing is one of the main causes of decreasing shoot sizes and hence of carbon imbalance, reduced growth and shoot mortality. The impact of fish farms on seagrasses, therefore, seems to be highly variable and depends on complex interactions between a large number of processes.

Dislocation of the polyethylene inlay due to anterior tibial slope in revision total knee arthroplasty

We report a case of dislocation of the polyethylene inlay in revision total knee arthroplasty. Eight days after revision arthroplasty due to a previous infection, the polyethylene inlay of a PCL- retaining cemented total knee arthroplasty dislocated at about 80 degrees of flexion on the CPM machine. Lateral X-ray examination revealed an anterior slope of the tibial cut of 5 degrees. Correction of the tibial slope to a posterior tibial slope of 7 degrees reduced the forces on the posterior aspect of the inlay and no redislocation occurred. The mechanisms causing tibial inlays to dislocate in TKA are analyzed and discussed.

Ultrasonographic and magnetic resonance images of rotator cuff lesions compared with arthroscopy or open surgery findings

Our purpose was to compare the accuracy of ultrasonography (US) and magnetic resonance (MR) in the diagnosis of rotator cuff injuries (focusing on supraspinatus tears) using arthroscopy or open surgery findings. Using US and MR, we studied all painful shoulders seen during 1998 in our orthopaedic unit. Diagnosis was confirmed in 61 cases. The diagnosis of full thickness rotator cuff tear was highly specific on both imaging techniques (100% for US and 97.1% for MR) but was not as sensitive on US (57.7%) as on MR (80.8%). The diagnosis of partial tear was acceptably specific (67.9% for US and 75.5% for MR) but was not sensitive (overall, 12.5% for US vs 50% for MR). The specificity of a US diagnosis of a tear allows us to recommend surgery, thus making it a good imaging technique for the initial study of painful shoulders. The low sensitivity makes it necessary to undertake an additional MR study. If the MR also discovers no pathology, the sensitivity based on the US and MR images (92.7%) can be sufficient to avoid a false-negative diagnosis.

Lipophilic extractives in process waters during manufacturing of totally chlorine free kraft pulp from eucalypt wood

The chemical composition of lipophilic extractives from process waters throughout a totally chlorine free (TCF) bleaching sequence after kraft pulping of eucalypt wood has been studied. These compounds are among the most problematic wood constituents for both TCF and zero liquid effluent (ZLE) processes, since they tend to accumulate in circuits resulting in the formation of the so-called pitch deposits causing serious problems in the pulp and paper industry. Pitch deposits collected at different parts of the pulp mill were also characterized and their composition compared with that of lipophilic compounds in process waters and Eucalyptus globulus wood. The identification of these compounds from process waters, wood and pitch deposits was performed by gas chromatography and gas chromatography-mass spectrometry using short- and medium-length high temperature capillary columns. Sterols, sterol esters, steroid ketones and steroid hydrocarbons were the main compounds identified. These chemical species arise from eucalypt wood extractives that survive the pulping and are released from pulp into the process waters during the bleaching process. Finally, they can deposit in pulp and on different parts of the mill or remain suspended in process waters being discharged in effluents.